(a) Field of the Invention
The present invention relates to a suitcase, and more particularly to a compound suitcase having a hard configuration and a soft configuration.
(b) Description of the Prior Art
Traditional suitcases come in two modes. One is a whole hard case made of a plastic material, as disclosed in U.S. Pat. No. 5,943,936. The other is a soft case made of a soft material, as disclosed in U.S. Pat. Nos. 7,147,089, 7,140,479, 6,883,654, 6,276,501, and 6,220,412.
The whole hard case can prevent the suitcase from being pressed and damaged. However, the suitcase is not provided with secondary bags. It is not convenient for the user to store small articles. The soft case can be provided with a bag by means of a zipper for the user to store small articles conveniently. However, the structure is not sufficiently strong. The fabric at the four corners may suffer a lot of wear and tear.
Furthermore, the suitcase made of soft fabrics needs the procedure of sewing the top and the bottom with the inner lining and the outer fabric of the front, the sides, and the rear. After sewing the top and the bottom, the other parts are assembled or sewn. For example, the rear side of the top is coupled with a retractable handle. The middle of the top is provided with an upper handle. The bottom is provided with rollers and support protrusions. The parts are connected to the case by rivets or sewing. The assembly procedure is more complicated.
A developed suitcase is composed of a hard plastic board and soft fabrics, as disclosed in U.S. Pat. No. 5,566,797. However, its top and bottom both have a single plank configuration, so the strength of the structure is weaker. The single plank configuration may be compressed to warp or deform, therefore the capavity of the suitcase to bear the external pressure is limited. In particular, when used as a boarding suitcase, the four corners of the top and the bottom can suffer wear and tear easily to damage the fabric at the four corners. In U.S. Pat. No. 5,566,797, the top and the bottom are hard plastic boards. But, the back board used as a support is a single hard plastic board. Because the capacity of the structure to bear the upper pressure is limited, it cannot be applied to a large-sized suitcase.
Accordingly, the inventor of the present invention has devoted herself with many years of practical experience to solve these problems.